1. Field
Embodiments relate to an apparatus and method for determining a weighting function for a linear predictive coding (LPC) coefficient quantization, and more particularly, to an apparatus and method for determining a weighting function having a low complexity in order to enhance a quantization efficiency of an LPC coefficient in a linear prediction technology.
2. Description of the Related Art
In a conventional art, linear predictive encoding has been applied to encode a speech signal and an audio signal. A code excited linear prediction (CELP) encoding technology has been employed for linear prediction. The CELP encoding technology may use an excitation signal and a linear predictive coding (LPC) coefficient with respect to an input signal. When encoding the input signal, the LPC coefficient may be quantized. However, quantizing of the LPC may have a narrowing dynamic range and may have difficulty in verifying a stability.
In addition, a codebook index for recovering an input signal may be selected in the encoding. When all the LPC coefficients are quantized using the same importance, a deterioration may occur in a quality of a finally generated input signal. That is, since all the LPC coefficients have a different importance, a quality of the input signal may be enhanced when an error of an important LPC coefficient is small. However, when the quantization is performed by applying the same importance without considering that the LPC coefficients have a different importance, the quality of the input signal may be deteriorated.
Accordingly, there is a desire for a method that may effectively quantize an LPC coefficient and may enhance a quality of a synthesized signal when recovering an input signal using a decoder. In addition, there is a desire for a technology that may have an excellent coding performance in a similar complexity.